Rheostat.



L. GRUMP.

BHEOSTAT.

APPLIOATIOK FILED NOV; 23 1910.

Patented Nov. 14, 1911.

1 T E E H S B T B E K S 2 H HEH awuemto'o Lloyd Grump PIANOOIAPNC0..wAsnmaTON. n4 6.

LLOYD GRUMP, OF CENTRALIA,'MISSOURI.

RHEOSTAT.

Specification of Letters Patent.

Patented Nov. 14, 1911.

Application filed November 23,1910. Serial No. 598,881.

To all whom it may concern:

Be it known that I, LLOYD CRUMP, a citizen of the United States,residing at Centralia, in the county of Boone, State of Missouri, haveinvented certain new and useful Improvements in Rheostats; and I dohereby declare the following to be a full, clear, and exact descriptionof the invention, such as will enable others skilled in the art to whichit appertains to make and use the same.

This invention relates to improvements in the devices for regulating theintensity of electrical currents, and the leading object in view is theprovision of a device comprising a receptacle of non-conducting materialhaving a fluid of high resistance therein and terminal plates adjustablein the receptacle and fluid whereby the resistance of an electricalcurrent may be varied at will.

WVith the above and other objects in view the invention consists incertain combinations, constructions and arrangement of parts, clearlydescribed in the following specification, and clearly illustrated in theaccompanying drawings, in which Figure 1 is a front elevation of theimproved device. Fig. 2 is a horizontal sectional view thereof. Fig. 3is a vertical sectional view showing the width of the terminal plates.Fig. 4 is a vertical sectional view showing the arrangement of thecontact brushes and the terminal plates. Fig. 5 is a detail perspectiveview of the terminal plates.

Referring to the accompanying drawings illustrating the practicalapplication of the invention 5 denotes the receptacle of the devicewhich is formed of glass or of other non-conducting material and formedwith flanges 6 whereby the receptacle may be attached to a wall or othersupport. A shaft 7 is mounted on the upper end of the receptacle 5 andon one of the ends of said shaft a turning knob 8 is fixed which isformed of hard rubber or other non-conducting material. The shaft 7carries two gears or pinions 9 spaced apart from each other and whichengage with the racks 10 formed on the vertical bar 11 of the terminalplate 12, which terminal plate is made of copper, brass, or likeconducting material. The bar 11 is secured to the bar 13 of the terminalplate 14 by means of insulated rivets 15, and a strip of insulatingmaterial 16 is placed between the bars 11 and 13 so that current willnot pass directly from one bar to the other.

The terminal plate 12 carries a vertical resilient arm or tongue 17which is secured at its lower end to said plate and which extends in aparallel plane with the arm 11 above said plate. The arm or tongue 17 isadapted to fit between the pinions 9 and hold the plates 12 and 14 intheir normal posi tions in the receptacle 5. A contact brush 18 issecured to the outer wall 5 of the receptacle 5 by a binding screw 19,and the inner end of the contact brush resiliently bears against thetongue or arm 17. The arm 13 of the terminal plate 14 is engaged by acontact brush 20 which is secured to the rear wall 5 of the receptacle 5by a binding screw 21. An insulated wire 22 is connected by the bindingscrew 19 to the brush 18 and to a second binding screw 23 secured on therear wall 5 of the receptacle 5. Circuit wires 24 are connected to thebinding screws 21 and 23. On the bottom 5 of the receptacle 5 aresilient contact plate 25 is fastened by a screw 26 or other likedevice. A cover 27 fits on the upper end of the receptacle 5 and saidcover is provided with a hollow vertical extension 28 which receives theupper ends of the vertical bars 11 and 13 of the terminal plates 12and14 respectively.

When current is supplied to the wires 24 and the shaft 7 is rotated bymeans of the knob 8 the terminal plates 12 can be lowered into the waterin the receptacle 5 so that the resistance to the flow of the currentmay be decreased or by a reverse movement the resistance increased. Whenthe terminal plates 12 are lowered to their lowermost limit they willcontact with a resilient contact 25 and the current will flow from onecontact plate through the contact device or plate 25 to the othercontact plate. By elevating the terminal plate above the water line thecurrent may be interrupted so that the lamp or lamps in the circuit ofthe wires 24 may be cut out.

What is claimed is 1. A rheostat comprising a receptacle ofnon-conducting material adapted to contain a. fluid of high resistance,a pair of terminal plates mounted for vertical movement within saidreceptacle, said plates being spaced and provided with upstanding arms,said arms being insulated from each other, one of said arms being incontact with a brush, the

other arm being provided with an ofi'set extension lying parallel tosaid arm and in contact with a second brush, and means for raising andlowering said plates.

2. A rheostat comprising a receptacle of non-conducting material adaptedto contain a fluid of high resistance, a pair of terminal plates mountedfor vertical movement within said receptacle, said plates being spacedand provided with upstanding arms, said arms being insulated from eachother, one of said arms being in contact with a brush, the other armbeing provided with an oiiset extension lying parallel to said arm andin contact with a second brush, means for raising and lowering saidplates, and a U-shaped contact member secured to the base of saidreceptacle, said member being arranged to connect the plates when thesame are at the limit of their downward movement.

3. A rheostat comprising a receptacle of non-conducting material adaptedto contain a fluid of high resistance, a pair of ter1ninal platesmovable in the receptacle and spaced apart from each other, each of saidterminal plates being formed with upstanding arms, said arms beinginsulated from each other, one of said arms being provided with a rack,a shaft mounted for rotation on the upper end of the receptacle, apinion mounted on the shaft to engage the rack, a resilient tonguemounted on one of the contact plates, a contact brush bearing againstthe tongue, a contact brush bearing against the other contact plate,wires connected with the contact brushes, and a cover for the receptaclehaving an upstanding hollow member receiving the arms of the terminalplates.

In testimony whereof, I ailiX my signature, in presence of twowitnesses.

LLOYD CRUMP. Vitnesses J. C. STEWART,

W. G. EATON.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. C.

